Expansion of T cells targeting multiple antigens of cytomegalovirus, Epstein–Barr virus and adenovirus to provide broad antiviral specificity after stem cell transplantation

Abstract

Background aims. Hematopoietic stem cell transplant (HSCT) is the treatment of choice for a proportion of patients with hematologic malignancies as well as for non-malignant diseases. However, viral infections, particularly Epstein–Barr virus (EBV), cytomegalovirus (CMV) and adenovirus (Ad), remain problematic after transplant despite the use of antiviral drugs. We have shown that cytotoxic T lymphocytes (CTL) generated against CMV-pp65, EBV and Ad antigens in a single culture are capable of controlling infections with all three viruses after HSCT. Although pp65-specific CTL have proved efficacious for the control of CMV infection, several reports highlight the importance of targeting additional CMV antigens. Methods. To expand multivirus-specific T cells with activity against both CMV-pp65 and CMV-IE-1, peripheral blood mononuclear cells (PBMC) were transduced with the adenoviral vector (Ad5f35-IE-1-I-pp65). After 9–12 days the CTL were restimulated with autologous EBV-transformed B cells transduced with the same Ad vector. Results. After 18 days in culture nine CTL lines expanded from less than 1.5 × 10⁷ PBMC to a mean of 6.1 × 10⁷ T cells that recognized CMV antigens pp65 [median 273 spot-forming cells (SFC), range 47–995] and IE-1 (median 154 SFC, range 11–505), the Ad antigens hexon (median 153 SFC, range 26–465) and penton (median 37 SFC, range 1–353), as well as EBV lymphoblastoid cell lines (median 55 SFC, range 9–301). Importantly, the T cells recognized at least two antigens per virus and lysed virus peptide-pulsed targets. Conclusions. CTL that target at least two antigens each of CMV, EBV and Ad should have clinical benefit with broad coverage of all three viruses and enhanced control of CMV infections compared with current protocols.

Key Words::

• adenovirus
• adoptive immunotherapy
• antiviral immunity
• cytotoxic T lymphocytes
• cytomegalovirus
• Epstein–Barr virus
• stem cell transplant

Acknowledgments

This work was supported by a grant from the Virginia and LE Simmons Family Foundation, a Specialized Centers for Cell-based Therapy Grant (NIH-NHLBI 1 U54 HL081007) and a Production Assistance for Cellular Therapies grant (N01-HB-37163).

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.